Typical microwave electrical devices have bonding pads on the top of the device to provide connections to external circuitry. Bonding wires are connected to these bonding pads to provide these connections. These bonding wires are typically fragile. They are susceptible to breaking when subjected to relatively high external forces or when placed under high pressure.
Other prior microwave electrical devices have beam leads on the top of the device to provide connections to external circuitry. These beam leads, however, are also relatively fragile.
The frailty of bonding wires or beam leads has a number of drawbacks. For example, resistors are typically used in air bag devices to protect people when involved in a motor vehicle collision. Resistors provide an explosive trigger when injected with a relatively high current, igniting explosive material to activate the air bag. Resistors thus provide a vital role for air bag devices.
In manufacturing air bag devices, resistors are subjected to relatively high external forces and pressure. A slurry is typically packed around the resistor in a relatively high pressure environment that can cause the bonding wires or beam leads attached to the resistors to break. Such breakage can result in the air bag not activating when needed in a collision.
Air bag devices may be provided with circuitry to continually monitor the resistors, ensuring they are properly connected to activate the air bag. The bonding wires or beam leads of the resistors may break after installation of the air bag device in an automobile or even after the sale of the automobile to a customer. This leads to increased costs for the manufacturer as new air bag devices must be reinstalled.
Redundant bonding wires or beam leads may be used to better ensure the resistors will activate the air bag. For example, 4 or 6 or 8 bonding wires may be connected to a single bonding pad of a resistor in hope that one of the bonding wires will not break when the slurry is packed around the resistor. This redundancy technique may reduce the number of faulty air bag devices at the time of manufacture. The bonding wires or beam leads may nevertheless break after installation or sale of the air bag device.